(1) Field of the Invention
The present invention relates to a bottle opener and, more particularly, to an improvement in a bottle opener which is capable of opening a bottle tightly sealed with a cork or the like in a simple and certain manner.
(2) Description of the Prior Art
A bottle opener is known with which a bottle is opened by inserting a penetrating needle into the cork sealing the bottle and introducing a gas such as carbon dioxide gas into the bottle through the penetrating needle.
As an example of such a known bottle opener, the one that is disclosed in the Japanese Patent Publication No. 42-17718 (1967) is illustrated in FIG. 1. Referring to this figure, numeral 51 denotes a cylinder which has at its bottom end an opening 51a through which extends a penetrating needle 53 with a through hole 52. The penetrating needle 53 is supported by its head portion 53a in the opening 51a. A groove 53b is formed at the head portion 53a. Numeral 54 denotes a bomb in which is filled an agent for generating gas such as carbon dioxide gas and has at its upper surface a gas outlet port 54a which is closed by a metal film. This bomb 54 is encased in the cylinder 51 and spaced from it by a distance which allows the gas to pass between the bomb 54 and the cylinder 51. Numeral 55 denotes a projecting rod fixed to a support 56. This projecting rod 55 is biased upward by a coil spring 57 and is disposed in a through hole 59 formed in a holding body 58. The projecting rod 55 also protrudes from a bottom plate 58a of the holding body 58 so as to face the gas outlet port 54a, that is, the metal film of the bomb 54. Numeral 60 denotes an outer cylinder fixed to the holding body 58, and together these constitute a cap body which is screwed to the cylinder 51. At the top surface of the support 56 is rotatably mounted a ball 61. Numeral 62 denotes a plunger with a hollow part 63, which has at its bottom surface a metal pressing part 64 for the ball 61. The metal pressing part 64 is disposed in a recess 65 of the outer cylinder 60 and is axially supported on a shaft 66. Numeral 67 denotes a coil spring inside the hollow part 63 which is interposed between the plunger 62 and the outer cylinder 60 so that the metal pressing part 64 does not constantly press the ball 61.
In a conventional bottle opener of the above construction, when the penetrating needle 53 is inserted into a cork sealing a bottle, and the plunger 62 is pressed while the cylinder 51 is held, the plunger 62 pivots about the shaft 66 against the biasing force of the coil spring 67 so as to press the ball 61. The projecting rod 55 is pressed downward by the ball 61 and breaks through the metal film of the gas outlet port 54a of the bomb 54. The gas in the bomb 54, such as carbon dioxide gas, flows out and passes through the space between the bomb 54 and the cylinder 51. The gas further flows inside the through hole 52, through the groove 53b of the penetrating needle 53, and into the bottle. The gas thus introduced inside the bottle raises the internal pressure and presses the cork upward. The cork is thus removed.
However, with this type of bottle opener, once the gas outlet port of the bomb is broken, the entire gas inside the bomb is exhausted through the through hole of the penetrating needle until the pressure inside the bomb equals the external pressure. Consequently, the bomb must be replaced every time a bottle is opened. This is extremely uneconomical. Further, the bottle itself often breaks before removing the cork, when the strength of the bottle used is smaller than the pressure of the gas to be introduced from the bomb into the bottle. The bottle opener of this type was further found to be defective for long-term use since the space between the bottom plate and the projecting rod and the space between the support and the through hole can become widened so that the gas to be introduced from the bomb into the bottle leaks out.